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(R)
L4947PD
5V-0.5A VERY LOW DROP REGULATOR WITH RESET
PRECISE OUTPUT VOLTAGE (5V 4%) OVER FULL TEMPERATURE RANGE (- 40 / 125 C) VERY LOW VOLTAGE DROP (0.75Vmax) OVER FULL T RANGE OUTPUT CURRENT UP TO 500mA RESET FUNCTION POWER-ON RESET DELAY PULSE DEFINED BY THE EXTERNAL CAPACITOR + 80V LOAD DUMP PROTECTION - 80V LOAD DUMP PROTECTION REVERSE VOLTAGE PROTECTION SHORT CIRCUIT PROTECTION AND THERMAL SHUT-DOWN (with hysteresis) LOW START UP CURRENT DESCRIPTION The L4947PD is a monolithic integrated circuit in HiPSO package specially designed to provide a stabilized supply voltage for automotive and industrial electronic systems. Thanks to its very low voltage drop, in automotive applications the L4947PD can work correctly even during the cranking phase, when the battery voltage could BLOCK DIAGRAM
PowerSO20 ORDERING NUMBER: L4947PD
fall as low as 6V. Furthermore, it incorporates a complete range of protection circuits against the dangerous overvoltages always present on the battery rail of the car. The reset function makes the device particularly suited to supply microprocessor based systems : a signal is available (after an externally programmable delay) to reset the microprocessor at power-on phase ; at power-off, this signal becomes low inhibiting the microprocessor.
INPUT 17
PNP OUTPUT TRANSISTOR ANTI SAT.
OUTPUT 3
DUMP PROTECT.
START
REF.
ERROR AMP.
OUTPUT CURRENT LIMITER
RESET OUTPUT 19
THERMAL PROTECTION
RESET CIRCUIT
GROUND This 1-20 is advanced information on a new product now in development or undergoing evaluation. Details are subject to change without 1-20 notice. 2 DELAY CAPACITOR
D94AT106
June 2000
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L4947PD
ABSOLUTE MAXIMUM RATINGS
Symbol Vi Parameter DC Input Voltage DC Reverse Input Voltage Transient Input Overvoltages : Load Dump : 5ms trise 10ms f Fall Time Constant = 100ms RSOURCE 0.5 Field Decay : 5ms tfall 10ms, RSOURCE 10 r Rise Time Constant = 33ms Low Energy Spike : trise = 1s, tfall = 500s, RSOURCE 10 fr Repetition Frequency = 5Hz Reset Output Voltage Junction and Storage Temperature Range Value 35 - 18 80 Unit V V V
- 80 100
V V
VR TJ, Tstg
35 - 55 to 150
V C
Note: The circuit is ESD protected according to MIL-STD-883C.
PIN CONNECTION (Top view)
GND DELAY CAP. +VOUT N.C. N.C. N.C. N.C. N.C. N.C. GND 1 2 3 4 5 6 7 8 9 10
D94AT107A
20 19 18 17 16 15 14 13 12 11
GND RESET N.C. +VIN N.C. N.C. N.C. N.C. N.C. GND
THERMAL DATA
Symbol Rth j-case Parameter Thermal Resistance Junction-case Max Value 3 Unit C/W
TEST CIRCUIT
IN Ci 100nF
17
3
OUT RP Co 47F(*) RESET OUTPUT
D94AT108
L4947PD
2 19 1-20
Cd
100nF
(*) Min 20F, ESR <10 over full temperature range RP (pull up resistor) and RL (load) are both equal to 1k.
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L4947PD
ELECTRICAL CHARACTERISTICS (refer to the test circuit, Vi = 14. 4V, Co = 47F, ESR < 10, Rp = 1K, RL = 1K, -40C TJ 125C, unless otherwise specified)
Symbol Vo Parameter Output Voltage Test Conditions Io = 0mA to 500mA Over Full T Range TJ = 25C Io = 0mA to (*) 500mA Vi = 6V to 26V ; Io = 5mA Io = 5mA to 500mA Io = 500mA, TJ = 25C Over Full T Range Io = 0mA, TJ = 25C Io = 0mA Over Full T Io = 500mA Over Full T Min. 4.80 4.90 6 5 15 0.40 5 6.5 110 - 0.5 Io = 350mA ; f = 120Hz Co = 100F ; Vi = 12V 5Vpp 1.5V < Vo < VRT (off), IR = 1.6mA 3.0V < Vo < VRT (off), IR = 8mA VO in Regulation, VR = 5V 1K Reset Pull-up to Vo Vo @ Reset Out H to L Transition Vo @ Reset Out L to H Transition VRT (on) -VRT (off) Vd @ Reset Out L to H Transition Vd @ Reset Out H to L Transition Vd = 3V, TJ = 25C Vo < VRT (off) Cd = 100nF, TJ = 25C 10 3.65 3.20 4.75 0.65 Vo - 0.15 VRT (off) + 0.05 0.05 4.00 3.55 0.45 20 0.55 20 1.20 30 Vo - 0.04 4.35 3.90 50 60 Typ. 5.00 5.00 Max. 5.20 5.10 26 50 60 0.55 0.75 10 13 180 Unit V V V mV mV V V mA mA mA mV/C dB
Vi Vo Vo Vi -Vo Iq Vo T SVR
Operating Input Voltage Line Regulation Load Regulation Dropout Voltage Quiescent Current
Temperature Output Voltage Drift Supply Volt. Rej.
Isc VR
Output Short Circuit Current Reset Output Saturation Voltage
0.50
0.80
1.50 0.40 0.40 50 1.0
A V V A V
IR VRT peak VRT (off) VRT (on) VHyst Vd
Reset Output Leakage Current Power On-Off Reset out Peak Voltage Power OFF Vo Threshold Power ON Vo Threshold Power ON-Off Hysteresis Delay Comparator Threshold
V V V V V V /A V ms
VdH Id Vdisch Td
Delay Comparator Hysteresis Delay Capacitor Charging Current Delay Capacitor Discharge Voltage Power on Reset Delay Time
(*) For a DC voltage 26 < Vi < 37V the device is not operating
FUNCTIONAL DESCRIPTION The L4947PD is a very low drop 5V/0.5A voltage regulator provided with a reset function and therefore particularly suited to meet the requirements of supplying the microprocessor systems used in automotive and industrial applications. The block diagram shows the basic structure of the device : the reference, the error amplifier, the driver, the power PNP, the protection and reset
functions. The power stage is a Lateral PNP transistor which allows a very low dropout voltage (typ. 400mV at TJ = 25C, max. 750mV over the full temperature range @ IO = 500mA). The typical curve of the dropout voltage as a function of the junction temperature is shown in Fig. 1 : that is the worst case, where IO = 500mA. The current consumption of the device (quiescent
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L4947PD
current) is maximum 13mA - over full T - when no load current is required. The internal antisaturation circuit allows a drastic reduction in the current peak which takes place during the start up. The reset function supervises the regulator output voltage inhibiting the microprocessor when the device is out of regulation and resetting it at the power-on after a settable delay. The reset is LOW when the output voltage value is lower than the reset threshold voltage. At the power-on phase the output voltage increases (see Fig. 2) and when it reaches the power-on VO threshold VRT (On) - the reset output becomes HIGH after a delay time set by the external capacitor Cd. At the power-off the output voltage decreases : at the VRT(Off) threshold value (VO-0.15V typ. value) the reset output instantaneously goes down (LOW status) inhibiting the microprocessor. The typical Figure 1: Typical Dropout Voltage vs. Tj (Io = 500mA). power on-off hysteresis is 50mV. The three gain stages (operational amplifier, driver and power PNP) require the external capacitor (Comin = 20F) to guarantee the global stability of the system. Load dump and field decay protections ( 80V), reverse voltage (- 18V) and short circuit protection, thermal shutdown are the main features that make the L4947PD specially suitable for applications in the automotive enviroment. EXTERNAL COMPENSATION Since the purpose of a voltage regulator is to supply and load variations, the open loop gain of the regulator must be very high at low frequencies. This may cause instability as a result of the various poles present in the loop. To avoid this instability dominant pole compensation is used to reduce phase shift due to other poles at the unity gain frequency. The lower the frequency of these others poles at the unity gain frequency. The lower the frequency of these other poles, the greater must be capacitor esed to create the dominant pole for the same DC gain. Where the output transistor is a lateral PNP type there is a pole in the regulation loop at a frequencybtoo low to be compensated by a capacitor which can be integrated. An external compensation is therefore necessary so a very high value capacitor must be connected from the output to ground. The paeassitic equivalent series resistance of the capacitor used adds a zero to the regulation loop. This zero may compromise the stability of the system since its effect tends to cancel the effect of the pole added. In regulators this ESR must be less than 3 and the minimum capacitor value is 47F.
Figure 2: Reset Waveforms: (1) Without External Capacitor Cd. (2) With External Capacitor Cd.
VO VRT(on) VRT(off) Vrthys
Vrpeak VR Vdthh Vdthl
(1)
(2)
Vrsat
Td
(2) VD
D94AT109
Vdisch
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L4947PD
DIM. A a1 a2 a3 b c D (1) D1 E e e3 E1 (1) E2 E3 G H h L N S T mm TYP. inch TYP.
MIN. 0.1 0 0.4 0.23 15.8 9.4 13.9
MAX. 3.6 0.3 3.3 0.1 0.53 0.32 16 9.8 14.5
MIN. 0.004 0.000 0.016 0.009 0.622 0.370 0.547
MAX. 0.142 0.012 0.130 0.004 0.021 0.013 0.630 0.386 0.570
OUTLINE AND MECHANICAL DATA
1.27 11.43 10.9 5.8 0 15.5 0.8 11.1 0.429 2.9 6.2 0.228 0.1 0.000 15.9 0.610 1.1 1.1 0.031 10 (max.) 8 (max.) 10
0.050 0.450 0.437 0.114 0.244 0.004 0.626 0.043 0.043
JEDEC MO-166
0.394
(1) "D and F" do not include mold flash or protrusions. - Mold flash or protrusions shall not exceed 0.15 mm (0.006"). - Critical dimensions: "E", "G" and "a3"
PowerSO20
N
N a2 b e A
R
c DETAIL B a1 E DETAIL A
DETAIL A e3 H
lead
D a3 DETAIL B
20 11
Gage Plane 0.35
slug
-C-
S E2 T E1 BOTTOM VIEW
L
SEATING PLANE G C
(COPLANARITY)
E3
1 10
h x 45
PSO20MEC
D1
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L4947PD
Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specification mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics. The ST logo is a registered trademark of STMicroelectronics (c) 2000 STMicroelectronics - Printed in Italy - All Rights Reserved STMicroelectronics GROUP OF COMPANIES Australia - Brazil - China - Finland - France - Germany - Hong Kong - India - Italy - Japan - Malaysia - Malta - Morocco Singapore - Spain - Sweden - Switzerland - United Kingdom - U.S.A. http://www.st.com
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